Mapping algorithm creates 3D maps in real time

The researchers tested their algorithm on videos taken with a Kinect camera. Applying their mapping technique to these videos, the researchers said they created rich, three-dimensional maps as the camera explored its surroundings.

As the camera returned to its starting point, the researchers found that after returning to a location recognised as familiar, the algorithm was able to stitch images together to effectively “close the loop,” creating a continuous, realistic 3D map in real time.

The technique is said to solve ‘loop closure’ or ‘drift’; a situation that can occur when a camera in motion introduces slight errors in the estimated path taken.

A doorway may shift slightly to the right, or a wall may appear slightly taller than it is. Over relatively long distances, these errors can compound, resulting in a disjointed map, with walls and stairways that don’t exactly line up.

In contrast, the new mapping technique uses the researchers’ algorithm to track a camera’s position at any given moment along its route. As the Kinect camera takes images at 30 frames per second, the algorithm measures how much and in what direction the camera has moved between each frame. The algorithm simultaneously builds up a 3D model, consisting of small “cloud slices” - cross-sections of thousands of 3D points in the immediate environment. Each cloud slice is linked to a particular camera pose.